This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Breast cancer is a very common disease, affecting 1 in 8 American women in their lifetimes and causing more than 40,000 deaths each year. The development of new non-invasive tools for screening, diagnosis, tumor staging, and treatment monitoring can help improve the quality of patient care. It has been previously shown by our group that quantitative MR spectroscopy can be used to give an early indication of a tumor's response to therapy. The clinical feasibility of this methodology is currently being investigated in a multi-site clinical trial (ACRIN 6657). The goal of this project is to develop and evaluate improved methods for performing quantitative MR spectroscopy in breast cancer. Several new MR spectroscopy techniques will be developed and compared to the standard ACRIN 6657 MRS protocol. There will be two phases to this project. Phase I will develop and compare these sequences on phantoms and normal volunteers. This phase will last approximately 6 months, at the end of which we will select the most promising of the sequence variations. In this phase we estimate that we will need one 1.5-hour session per week for each of 20 weeks (30 hrs). In Phase II, we will perform a normal reproducibility study on a series of 10 subjects, each studied twice. The acquisition protocol will consist of conventional MRI, followed by the standard ACRIN 6657 MRS acquisition, then followed by the experimental MRS methods.